Barbershop music is a style of a cappella close harmony and vocal harmony, or unaccompanied vocal music, characterized by consonant four-part chords for every melody note in a primarily homorhythmic texture. Each of the four parts has its own role: generally, the lead sings the melody, the tenor harmonizes above the melody, the bass sings the lowest harmonizing notes, and the baritone completes the chord, usually below the lead. Short segments of bass or tenor melody, for variety or to feature particular singers, are not uncommon, but the bulk of the melody must be in an "inner voice" (lead or baritone; in practice almost always lead). In addition, parts other than lead may take the melody in passing tones to avoid awkward voice leading, in tags or codas, or when some appropriate embellishment can be created. One characteristic feature of barbershop harmony is the use of what is known as "snakes" and "swipes". This is when a chord is altered by a change in one or more non-melodic voices. Occasional passages may be sung by fewer than four voice parts.

Barbershop music is generally performed by either a barbershop quartet, a group of four singers which sings four-part harmony, or a barbershop chorus, which closely resembles a choir except for the arranging and performance style of the music.

According to the Barbershop Harmony Society (BHS), "Barbershop music features songs with understandable lyrics and easily singable melodies, whose tones clearly define a tonal center and imply major and minor chords and barbershop (dominant and secondary dominant) seventh chords that resolve primarily around the circle of fifths, while making frequent use of other resolutions." Slower barbershop songs, especially ballads, often eschew a continuous beat, and notes are often held (or sped up) ad libitum.

Aside from the bass, the voice parts in barbershop singing do not correspond closely to their classical music counterparts; the tenor range and tessitura are similar to those of the classical countertenor (including the fact that they sing their highest notes primarily in falsetto, as a countertenor would), the baritone resembles a high lyric baritone in range and a tenor in tessitura, and the lead generally corresponds to the tenor of classical repertoire, with some singers possessing a tessitura more similar to that of a high baritone. Barbershop singing is performed both by men's and women's groups; the elements of the barbershop style and the names of the voice parts are the same for both.

Characteristics Ringing chords

The defining characteristic of the barbershop style is the ringing chord, one in which certain overtones of the four voices reinforce each other, sometimes so strongly that the overtone is perceived by the listener as a distinct tone, even though none of the voices are perceived as singing that tone. This effect occurs when the chord, as voiced, contains intervals which have strongly reinforcing overtones (fifths and octaves, for example) that fall in the audible range; and when the chord is sung in perfect just tuning without excessive vibrato. Both of these characteristics are important in many styles of singing, but in barbershop there is an extreme emphasis on them that tends to override other musical values. For example, favored chords in the jazz style are characterized by intervals which do not audibly ring, such as diminished or augmented fifths. For another example, barbershop music is always a cappella, because the presence of fixed-pitch instruments (tuned to equal-temperament rather than just temperament), which is so highly prized in other choral styles, makes perfect just tuning of chords impossible.

The physics and psychophysics of the effect are fairly well understood; it occurs when the upper harmonics in the individual voice notes, and the sum and difference frequencies resulting from nonlinear combinations within the ear, reinforce each other at a particular frequency, strengthening it so that it stands out separately above the blended sound. The effect is audible only on certain kinds of chords, and only when all voices are equally rich in harmonics and justly tuned and balanced. It is not heard in chords sounded on modern keyboard instruments, due to the slight tuning imperfection of the equal-tempered scale.

Gage Averill writes that "Barbershoppers have become partisans of this acoustic phenomenon" and that "the more experienced singers of the barbershop revival (at least after 1938) have self-consciously tuned their dominant seventh and tonic chords in just intonation to maximize the overlap of common overtones." However, "In practice, it seems that most leads rely on an approximation of an equal-tempered scale for the melody, to which the other voices adjust vertically in just intonation."

What is prized is not so much the "overtone" itself, but a unique sound whose achievement is most easily recognized by the presence of the "overtone". The precise synchrony of the waveforms of the four voices simultaneously creates the perception of a "fifth voice" while at the same time melding the four voices into a unified sound. The ringing chord is qualitatively different in sound from an ordinary musical chord e.g. as sounded on a tempered-scale keyboard instrument.

Most elements of the "revivalist" style are related to the desire to produce these ringing chords. Performance is a cappella to prevent the distracting introduction of equal-tempered intonation, and because listening to anything but the other three voices interferes with a performer's ability to tune with the precision required. Barbershop arrangements stress chords and chord progressions that favor "ringing", at the expense of suspended and diminished chords and other harmonic vocabulary of the ragtime and jazz forms.

The dominant seventh-type chord is so important to barbershop harmony that it is called the "barbershop seventh". BHS arrangers believe that a song should contain dominant seventh chords anywhere from 35 to 60 percent of the time (measured as a percentage of the duration of the song rather than a percentage of the chords present) to sound "barbershop".

Historically barbershoppers may have used the word "minor chord" in a way that is confusing to those with musical training. Averill suggests that it was "a shorthand for chord types other than major triads", and says that the use of the word for "dominant seventh-type chords and diminished chords" was common in the late nineteenth century. A 1910 song called "Play That Barber Shop Chord" (often cited as an early example of "barbershop" in reference to music) contains the lines:

'Cause Mister when you start that minor partI feel your fingers slipping and a grasping at my heart,Oh Lord play that Barber shop chord!

Averill notes the hints of rapture, "quasi-religion" and erotic passion in the language used by barbershoppers to describe the emotional effect. He quotes Jim Ewin as reporting "a tingling of the spine, the raising of the hairs on the back of the neck, the spontaneous arrival of goose flesh on the forearm ... the fifth note has almost mysterious propensities. It's the consummation devoutly wished by those of us who love Barbershop harmony. If you ask us to explain why we love it so, we are hard put to answer; that's where our faith takes over." Averill notes too the use of the language of addiction, "there's this great big chord that gets people hooked." An early manual was entitled "A Handbook for Adeline Addicts".

He notes too that "barbershoppers almost never speak of 'singing' a chord, but almost always draw on a discourse of physical work and exertion; thus, they 'hit', 'chop', 'ring', 'crack', 'swipe', and 'bust.' Vocal harmony is interpreted as an embodied musicking. Barbershoppers never lose sight (or sound) of its physicality."

Historical origins

English "barber's music" was described in the 17th century by Samuel Pepys as amateur instrumental music. The Encyclopædia Britannica considers the 19th-century origins of the quartet style as "obscure", possibly referring back to barber's music, or dating to when barbershops served as community centers, where men would gather for social and musical activities with barbers traditionally being musicians.

Historical memoirs and journalism indicate a strong tradition of quartet singing among young African-American men, gathering informally to "crack up a chord". This was acknowledged as early as 1882, when a New York Age writer traced the development of this singing as a home-grown amusement, arising from the exclusion of Black people from theaters and concert halls. Jazz musician Louis Armstrong told of having harmonized on New Orleans street corners as a boy, and NAACP executive secretary James Weldon Johnson "grew up singing barbershop harmony".

Later, white minstrel singers adopted the style, and in the early days of the recording industry their performances were recorded and sold. Early standards included songs such as "Shine On, Harvest Moon", "Hello, Ma Baby", and "Sweet Adeline". Johnson noted in the 1920s how the genre had already crossed racial barriers.

Barbershop music was very popular between 1900 and 1919, and some of the most popular quartets were the Haydn Quartet, the American Quartet, and the Peerless Quartet. Modern barbershop quartets often costume themselves in gaudy versions of the vaudeville dress of this time, with boaters and vertically striped vests. Composer and pianist Scott Joplin incorporated a barbershop quartet into his 1911 opera Treemonisha. The genre gradually faded into obscurity in the 1920s, although barbershop-style harmonies remained in evidence in a cappella forms of traditional black gospel and white gospel.

The modern era of barbershop music is accepted to have begun with a 1940s revival, though opinions as to the genre's origins vary with respect to race, gender, region, and context.Döhl, Frédéric (2014): From Harmonic Style to Genre. The Early History (1890s–1940s) of the Uniquely American Musical Term Barbershop. American Music 32, no. 2, 123–171, here 123–124. "In recent years, new insights and greater clarity have been acquired, which include aesthetic issues relating to sound, some answers to questions of race, gender, and other social factors shaping the genre, and exploration of the ideology surrounding the so-called revival around 1940. Still, the debate about the origins of this genre seems to be widely unsettled. The current models that chart the birth of barbershop harmony are diverse and often contradictory with regard to categories such as race, gender, regional context, social environment, amateur or professional, impromptu or composed-arranged, and highbrow or lowbrow."

Other researchers argue that today's barbershop music is an invented tradition related to several musical features popular around 1900, including quartet singingBrooks, Tim (2005): Lost Sounds. Blacks and the Birth of the Recording Industry, 1890–1919. Urbana-Champaign/IL: University of Illinois Press and the use of the barbershop chord, but effectively created during the 1940s in the ranks of the Barbershop Harmony Society whilst creating a system of singing contests and its contest rules.Averill, Gage (2003): Four Parts, No Waiting. A Social History of American Barbershop Harmony. New York: Oxford University Press.Garnett, Liz (2005): The British Barbershopper: A Study in Socio-musical Values. London: Ashgate.

Organizations Barbershop music is promoted through the use of competition for quartets and choruses run by not-for-profit organizations. Barbershop organizations often provide judging, education, coaching and promotion services for local choruses and quartets.

United States